Strapping machines are in widespread use for securing straps around loads. There are two principle types of strappers. One type is a manually operated hand tool that can be used, for example, around a job site. Another type of strapper is a stationary arrangement in which the strapper is fabricated as part of an overall apparatus. In such a strapper, the strapping head and drive mechanisms are typically mounted within a frame. A chute is likewise mounted to the frame, through which the strapping material is fed.
In a typical, stationary strapper, the strapping head is mounted at about a work surface, and the chute is positioned above the work surface and above the strapping head. Strap material is fed to the strapping head by a set of feed and take-up wheels. The strapping material is fed, by the feed wheels past the strapping head, around the chute and back to the strapping head. The free end of the strapping material is then grasped, such as by a first part of a gripping arrangement. The strap is then retracted by the take-up wheels and tensioned around the load. The tensioned strap is then gripped by a second part of the gripping arrangement. A cutter in the strapping head then cuts the tensioned strap (from the source or supply) and the strapping head forms a seal in the strapping material, sealing the strapping material to itself around the bundled load.
Strapping operations are typically secondary operations in that these operations are used for bundling or securing individual items into a single, large load. The straps themselves are not of commercial concern to the end user; rather, it is the bundled items that are of concern. As such, it is important to be able to strap and move the items quickly and in a cost effective manner.
To this end, improvements have been made to strapping machines. One such improvement includes an auto re-feed arrangement, such as that disclosed in Bell, et al., U.S. Pat. No. 5,640,899, commonly assigned herewith. In such an arrangement, in the event of a misfeed of strapping material, the misfed strap is cut and ejected from the machine. Fresh strapping material is then automatically re-fed by the feed wheels through the strapping head and around the load. It has been found that such an arrangement saves considerable time and labor vis-a-vis removing the misfed or snapped strap and refeeding strap material into the strapper.
One drawback to the known re-feed arrangements is that they require separate feed and take-up wheels. That is, a pair of wheels (generally one driven and one idle) is required to feed the strapping material through the strapping head and the chute. A second, separate set of wheels (again, one driven and one idle) is required to take-up or retract the strap in order to tension the strap around the load. While these automatic re-feed arrangements have been found to save considerable time and labor, the requisite two pairs of wheels introduce additional maintenance concerns as well as timing arrangements with respect to the overall operation of the machine.
It has also been found that typically, these stationary types of strappers are designed and constructed such that the feed and take-up mechanism is located near to the strapping head. Because of the proximity of the feed and take-up arrangement to the strapping head, two sets of feed and take-up wheels are required in order to meet the overall operating requirements, given the physical constraints of the equipment.
Present designs of stationary strappers, which include a closely located feed and take-up mechanism to the strapping head, also include guide paths to, from and between components that are all fixedly mounted to the machine. In the event of maintenance or repair, the machine must be taken out of service for the duration of that work. In addition, skilled technicians are generally required to tend to the machine during the entirety of the maintenance or repair procedure.
Accordingly, there exists a need for a strapping machine that utilizes modular components, specifically for the drive and sealing functions. Desirably, such a modular design permits positioning the feed/take-up mechanism at a location such that only a single set of wheels is required. In such an arrangement, the modular components are readily removed and installed in machines to minimize the xe2x80x9cdown timexe2x80x9d of such machines. Most desirably, such modular components are readily installed and removed, with minimal or no tools. In such a strapper, an auto re-feed arrangement is desirable without the use of separate feed and take-up reels.
A strapping machine for positioning a strapping material around an associated load and sealing the strapping material to itself around the load, includes a modular strapping head assembly and a modular feed assembly. The strapping machine includes a frame, a chute defining a strap path and having an opening therein that is mounted to the frame, the modular feed assembly mounted to the frame and the modular strapping head assembly mounted to the frame. A guide is mounted to the frame between the feed assembly and the strapping head.
The feed assembly is mounted to the frame by a first aligning and mounting assembly. The feed assembly is configured to feed the strapping material therethrough. The modular feed assembly is independently removable from the frame. In a preferred configuration, the feed assembly is mounted to the frame in an configuration such that it is installed in and removed from the frame without the use of tools.
The strapping head is mounted to the frame by a second aligning and mounting assembly independent of the first mounting assembly, the feed assembly and the guide. The strapping head assembly is, like the feed assembly, independently removable from the frame. The strapping head is configured for receipt in the chute opening and to provide a conveyance path for the strapping material from the guide to the chute. The strapping head assembly is further configured to receive a free end of the strapping material and to seal the strapping material to itself. In a preferred configuration, the strapping head assembly is mounted to the frame in a configuration such that it is installed in and removed from the frame without the use of tools.
The guide is mounted to the frame independent of the feed assembly. The guide is configured to receive the strapping material from the feed assembly and to provide a path for the strapping material to the head and toward the chute.
In one embodiment, the first aligning and mounting assembly (the assembly for mounting the feed assembly) includes first and second cooperating, aligning members for aligning the feed assembly on the frame and a securing member for securing the feed assembly to the frame. Likewise, the second aligning and mounting assembly can include first and second cooperating, aligning members for aligning the strapping head assembly to the frame and a securing member for securing the strapping head assembly to the frame.
In one configuration, the first aligning member is formed as a base portion having a receiving member and the second aligning member is formed as a nesting member configured for receipt in the receiving member. The receiving member can be formed having at least one slot or notch and the nesting member has a shape complementary to the at least one notch.
In a current configuration, the receiving member is formed having a pair of rounded slots or notches and the nesting member is formed as a cylindrical element, such as a bar, configured for receipt in each of the pair of notches. For the feed assembly, the receiving member can be disposed on the feed assembly and the nesting member can be formed on the frame. For the strapping head, the receiving member can be disposed on the frame, and the nesting member can be formed on the strapping head assembly.
The securing member can include a clamping element. Preferably, the clamping element is a hand-tightened element. The hand-tightened element can be a threaded stud threadedly engageable with the feed assembly, The frame can be formed having a notch for receiving the stud. To facilitate installation, the notch can have an enlarged entrance region.
In such an arrangement, the location of the feed assembly vis-à-vis the strapping head permits use of a feed assembly having one pair of wheels for feeding the strapping material for retracting the strapping material.
In an alternate embodiment, in mounting the strapping head, the first aligning member can be configured as a rail and the second aligning member as a rail pin configured for traversing along the rail. Preferably, this embodiment includes a pair of rails and plurality of rail pins for traversing along the rails. The rail pins are can be mounted to the strapping head assembly and the pair of rails are preferably mounted to the frame on opposing sides of the chute, at about the chute opening. In a current embodiment, the rails are formed having upper and lower flanges for maintaining the rail pins therebetween.
The securing member can be formed as a latch assembly. In one embodiment, the latch assembly is mounted to the rail and includes a detent for engaging at least one of the rail pins to maintain the strapping head assembly in place between and along the rails. The latch assembly can include a release portion for engaging and disengaging the detent with the rail pin. In a preferred embodiment, a biasing element, such as a coil spring, biases the detent to engage the rail pin. Alternately, the latch assembly can be pivotally mounted to the strapping head for engaging a detent on one of the rails.
The present invention further contemplates a modular strapping head assembly for use with the strapping machine. The modular strapping head assembly includes a body, a strap receiving portion, a strapping material sealing portion, and an aligning and mounting portion. The aligning and mounting portion is configured for independent, tool-less installation and removal from the strapping machine. The aligning and mounting portion is adapted for positioning the strapping head at the chute opening and maintaining the strapping head at the chute opening, and further provides a conveyance path for the strapping material from into the chute.
In one configuration, the aligning and mounting portion includes a plurality of rail pins cooperable with associated rails positioned on the strapping machine. At least one of the rail pins is further configured for cooperation with an associated retaining assembly positioned on the strapping machine to maintain the strapping head at the chute opening. Alternately, the retaining assembly is mounted to the strapping head assembly and cooperates with one of the rails to maintain the strapping head at the chute opening.
Alternately, the aligning and mounting portion includes one of a cooperative nesting and receiving member, and a clamping member. The nesting member is configured for receipt in the strapping machine to position the strapping head assembly in place. The clamping member engages the strapping machine to retain the strapping head assembly in place.
The present invention further contemplates a modular feed assembly for use with the strapping machine. The feed assembly includes a body, a drive, a pair of wheels, one of the pair of wheel being operably connected to the drive, a strap guide disposed over at least a portion of each of the pair of wheels, and an aligning and mounting portion.
The aligning and mounting portion is configured for independent, tool-less installation and removal of the modular feed assembly from the strapping machine. The aligning and mounting portion is adapted for positioning the feed assembly at an associated second strap guide, which strap guide provides a conveyance path for the strapping material from the modular feed assembly to the strapping head.
In a preferred embodiment, the aligning and mounting portion includes one of a cooperative nesting and receiving member, and a clamping member. Preferably, the aligning and mounting portion includes the nesting member, which member is configured for receipt in the strapping machine (having the receiving member) to position the strapping head assembly in place. The clamping member engages the strapping machine to retain the strapping head assembly in place.
The strapping machine can further include quick-connect electrical connectors to further facilitate modularity, easing installation and removal of the modular components. More preferably, the frame and strapping head include mating portions of such a connector to facilitate removal and installation of the strapping head.
In a current embodiment, as set forth above, because of the positioning of the feed assembly vis-a-vis the strapping head, the feed assembly need include only one pair of wheels for feeding and retracting the strapping material.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.